House Republicans are pushing their leaders to ratchet up their demands for passing a payroll tax cut, throwing a new wrinkle into efforts to quickly cut a bipartisan deal and end the year without partisan brinkmanship.

The growing problem: A large group of lawmakers is looking to exact some measure of political victory against the Democratic Senate and President Barack Obama and to stiffen their negotiating position with the upper chamber.

They’re peeved that last month, their leaders supported a government funding measure that saw 100 defections. And now, they’re being pressured to pass the president’s top legislative priority: the payroll tax cut.

So while much of Washington may be ready to act, there remains a high degree of uncertainty among the House majority.

By Tuesday evening, there were fears at the highest rungs of House GOP leadership that their conference was nowhere near the 218 votes needed to approve a package to extend the provisions — a failure that aides say would hurt morale in the party.

It may not matter practically — Democrats could potentially make up the difference to give Obama the win — but the growing thought within House GOP circles is that they cannot go down without a fight.

The concerns were expressed at a leadership meeting Tuesday afternoon. House Majority Leader Eric Cantor (R-Va.) was pushing the leadership to take up repatriation — a process by which corporations could bring profits back onshore at a lower tax rate — as part of a year-end package. And House Republican Conference Chairman Jeb Hensarling of Texas — burned by a failure on the supercommittee, which he co-chaired — also seemed ready for a fight and is advocating for some entitlement reform alongside the tax holiday.

Then, there’s Speaker John Boehner (R-Ohio). He supports the policies in principle but does not think the year-end compromise is the proper vehicle. He even pushed back last week against Cantor’s call to add to a year-end package a delay of the first-year automatic cuts that will take place because of the supercommittee’s failure. And there are messaging challenges, as well.

Congressional scorekeepers say repatriation could add billions to the deficit. Some Republicans don’t support offsetting those cuts, but they do support paying for the payroll tax holiday.

All this needs to be resolved soon or the Social Security payroll tax will go up next year for every working American; unemployment benefits will run dry; and doctors who treat Medicare patients will have their fees cut. House Republicans are expected to delay any action until next week.

Even though it’s late in the game, Republicans want their leaders to be ambitious. Rep. Jeff Flake (R-Ariz.), a conservative running for the Senate, said if “we don’t have the guts to do entitlement reform, then we shouldn’t be extending this cut.”

But the fight within the House Republican Conference differed markedly from the expectations on both sides of the aisle in the Senate that a deal could be worked out.

Both Republican Sens. John Cornyn of Texas and Lamar Alexander of Tennessee, who voted against extending the payroll tax break over concerns that it would hurt Social Security, said Tuesday they’d be open to considering supporting it as part of a broader year-end package.

“People would like to get their work done and go home,” Cornyn said when asked about eleventh-hour brinkmanship.

Other opponents of a payroll tax break — and a year-end spending bill that could cost about $1 trillion — concede that they have little chance to block an expected deal on both issues cut by the leadership from both parties.

“We won’t have the votes to stop it — everyone is going to want to go home for Christmas,” conceded Sen. Jim DeMint (R-S.C.), a frequent critic.

Democratic leaders continued to push their plan to extend the payroll tax break that’s funded, in part, by a roughly 2 percent surtax on those earning more than $1 million. But the plan is likely to fail amid GOP opposition.

If both the House plan and the Senate Democratic proposal fail, the two sides will try to cut a deal.

“It’s Christmas, and I think there is now an acknowledgment that we need to have an orderly end to the session,” said Sen. Ben Cardin (D-Md.). “And I think most of the components are well known.”

Still, there’s much work to do, given the two sides are squabbling over how to pay for an extension of the payroll tax break, jobless benefits and to change the formula for reimbursing Medicare physicians.

But so far in the proposals drafted by both parties, it appears that Democratic and Republican leaders are closer to a deal than their public rhetoric suggests.

Under the $185 billion plan authored by Sen. Bob Casey (D-Pa.), the payroll tax break would be lowered to 3.1 percent in order to avoid the 6.2 percent rate that would hit some 160 million workers if Congress doesn’t act by year’s end.

To pay for the cut, Democrats call for increasing the fees that Fannie Mae and Freddie Mac charge mortgage lenders, which would raise some $38.1 billion, an idea borrowed by negotiators on the bipartisan supercommittee. They also would cut off food stamp and unemployment benefit assistance for millionaires, a proposal pulled from a payroll plan floated last week by Senate Minority Leader Mitch McConnell (R-Ky.).

Under a plan being considered by Boehner and his leadership team, Congress would extend for one year jobless benefits, make the so-called doc fix for Medicare physicians for two years and extend the payroll tax at the current lower rate of 4.2 percent that was enacted last year.

Revenue would also be raised through fees on Fannie Mae and Freddie Mac, spectrum auctions for wireless broadband services, reforms to the flood insurance programs and cuts to food stamps and jobless benefits for those earning more than $1 million.

But in what could provoke a fight with Democrats, the GOP wants to freeze the pay of federal workers for the next two years, cut Environmental Protection Agency research grants and increase premiums for rich Medicare beneficiaries.

Both sides continue to look for new streams of revenue to pay for the year-end package — and the idea of using war savings to at least pay for the perennial problems of the doc fix and to fix the alternative minimum tax is being pushed by a handful of members in both parties.

But there’s also a contradictory thought, as put by a House GOP aide.

“If Senate Democrats and President Obama drop their job-killing small-business tax hike, I would think we can find common ground on a package that extends the current tax holiday, protects Social Security, reforms unemployment insurance and doesn’t add to the deficit,” the aide said.

Republicans, however, will have to concede, as well, most notably over their demands to tweak Medicare, and they’ll have to back the payroll tax cut that a majority of Senate Republicans voted against last week.

Another calculation for House Republicans is their vote timing. They are not sure when Senate Majority Leader Harry Reid (D-Nev.) will arrive at a package that could garner the 60 votes needed to avert a filibuster, throwing into flux a decision on whether to move forward with their own package or wait for a compromise.

If Republicans move on their own plan, they will embrace a slew of controversial proposals and risk having their members get hooked on provisions that won’t become law.

But they could lose leverage if they wait for the Senate. The speaker wants to adjourn by Dec. 16.